**Al-Cr-Nb-N**

Fcc-structured Al26Cr24N50, Al23.5Cr19Nb2.5N50 and Al27.5Cr17.5Nb5N50 coatings were deposited by cathodic arc evaporation. The hardness increased slightly with the addition of Nb from 31 to 32 GPa at room temperature, but the increase in hardness is more pronounced after annealing at a temperature of around 1000 ◦C (plus 3 GPa). The phase stability was shifted to include higher temperatures with the addition of Nb, but the oxidation resistance decreases [108].

#### **Al-Cr-W-N**

(AlCr)N and (AlCrW)N coatings have been deposited by the cathodic vacuum arc method using cathodes of Al70Cr25W5 and Al70Cr30. The coating had a W content that was about the same as in the cathode and an Al/Cr ratio of 2, (Al64Cr31W5)N. Oxidation tests showed that the (AlCrW)N coating had higher oxidation stability than the (AlCr)N coating at 1100 ◦C; however, it was worse than (AlCr)N at 900 ◦C [81].

4.1.3. Coatings with the Addition of Non-Ferrous Metals
